[C:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1[NH:10][C:11](=[O:16])[CH:12]=[C:13]([CH3:15])[CH3:14])(=O)[CH3:2].[CH:17]([NH2:20])([CH3:19])[CH3:18].[BH4-].[Na+]>CC(C)[O-].[Ti+4].CC(C)[O-].CC(C)[O-].CC(C)[O-]>[CH:17]([NH:20][CH:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1[NH:10][C:11](=[O:16])[CH:12]=[C:13]([CH3:15])[CH3:14])[CH3:2])([CH3:19])[CH3:18]The product of Example 10 (217 mg, 1.0 mmol) was placed in a flame dried 25 mL round bottom flask, and flushed with Ar(g). The flask was charged with 8 mL of absolute ethanol, followed by isopropylamine (85.2 μL, 1.0 mmol), followed by the addition of titanium(IV) isopropoxide (0.59 mL, 2.0 mmol). The reaction was allowed to proceed at room temperature for 16 hours. After this time sodium borohydride (60 mg, 1.5 mmol) was added slowly over 10 minutes, and the mixture was allowed to stir for an additional 2 hours. The white precipitate was then filtered off, and washed with dichloromethane (20 mL). The washings were then collected, transferred to a separatory funnel, and washed successively with 1N NaOH (2×15 mL), and brine (1×15 mL). The organic layer was then dried over magnesium sulfate, filtered and evaporated to yield a crude oil, which was purified by column chromatography in ethyl acetate-hexane (3:7), to yield 216 mg of a yellow oil (83% yield). 1H NMR (360 MHz, CDCl3) δ 8.46-8.36 (m, 1H), 7.26-7.17 (m, 1H), 7.07-7.00 (m, 1H), 6.99-6.90 (m, 1H), 5.70-5.66 (m, 1H), 4.08 (q, J=6.5 Hz, 1H), 2.71 (sep., J=6.5 Hz, 1H), 2.25 (d, J=0.8 Hz, 3H), 1.90 (d, J=1.2 Hz, 3H), 1.38 (d, J=6.5 Hz, 3H), 1.09 (d, J=6.5 Hz, 3H), 1.05 (d, J=6.5 Hz, 3H).
Wird geladen…
